CODEWITHSUNDEEP
c++visual-studio-2010filevisual-c++command-line-arguments
user2775084
user2775084

Reputation: 105

File as Command Line arguments

I am new to C++ and I am learning with Visual Studio. I want to make a small program that reads a text from the command line and opens the text. I know that my program has to start like this: 

  int main (int argc, char *argv[] ){

    ifstream File( argv[1] )

But I am super confused on how to run it from the Visual Studio Command Prompt. I know there are a lot of questions like this but I still haven't found what I am looking for. I read that you have to go to properties, Debug and change the command line arguments, but what exactly do I need to put in there? And what should I type in the VS Command Prompt.

Thank you!

Upvotes: 1

Views: 8847

Answers (2)

SHR
SHR

Reputation: 8313

From menu find: Project->Properties. Or from the Solution Explorer tree right click on the project and select Properties.

Now, in the opened dialog left pane select: Configuration Properties->Debugging

Then in the right pane grid find the line titled: Command Arguments

Fill it with the input file name (I think you better put it there as a full path, if there is a space in the path use with double quotas. like this:

Without space:

filepathwithoutspace.txt

or with spaces:

"file path with spaces.txt"

Good luck.

Upvotes: 3

James Kanze
James Kanze

Reputation: 153909

For starters, your code should not start like that: before passing argv[1] to std::ifstream::ifstream, you should verify that there is an argument, and output an error message otherwise. As it is, you could end up passing a null pointer to the constructor of ifstream, which will result (normally) in a program crash.

As to how to run it: where did you put the executable? If you're in the Visual Studio Command Prompt window, and have invoked cl, then by default, the executable should be in the local directory. Just enter .\name, where name is the name of your program. If you've actually compiled it from within the IDE, then in the command window, you should use cd to navigate to where the executable was generated (which you can find out from your properties), and invoke it as above; or you can simply specify the path completely: c:\Users\me\whereeverIPutTheThing\name.

If you want to debug (using the debugger), you need to specify: 1) the name of the executable (but the default should be good), 2) the parameters to pass it (what you want to see in argv[1]—don't forget the quotes if it has a space in it), and 3) the directory where the executable should run. The second and third are somewhat interdependant: you can, for example, specify just the filename in 2, and the path where the file is located in 3, or you can specify the complete path to the filename in 2, and forget about 3. Or use a combination of the two: in practice, I tend to do everything from the root directory of the project, so I'd specify a path relative to this directory, and then the path from my project file to this root in 3. (The way we have things set up, this is ..\..\.., but I think you'll find it somewhat shorter.)

Upvotes: 2

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